Stand to be corrected but believe I am right in saying...
1. AFS are about to or have voted on pay issues.
2. AFS (certainly at LGW) are the initial response to ALL fire calls at the airport including 'domestic', (auto alarms, smoking bins,etc) fire calls and are backed up by the local authority service.
3. Not sure about the exact details but I am sure that AFS have some form of over manning/appliance cover to allow for more than one incident occuring at the same time.